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CVE-2017-18122

SimpleSAMLphp Signature validation bypass

8.1 HighFix available

CVE-2017-18122 is a high vulnerability (CVSS 8.1) in Simplesamlphp, published February 2, 2018. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.09%, the 65th percentile. Fixed in simplesamlphp/simplesamlphp 1.14.17.

A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. A SimpleSAMLphp Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
High

Exploit likelihood

1.09%Up 0.3 points since Apr 14, 2021
90%50%10%1%

What each source reports

NVD Score used 8.1

A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. A SimpleSAMLphp Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP.

Record
CVE-2017-18122
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0
6.8 MediumAV:N/AC:M/Au:N/C:P/I:P/A:P
Weakness
CWE-347
Updated
2026-11-02
CVE List No score

A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. A SimpleSAMLphp Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP.

Record
CVE-2017-18122
Updated
2026-11-02
EUVDEUVD-2022-4278 No score

A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. A SimpleSAMLphp Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP.

Record
EUVD-2022-4278
Updated
2026-11-03
GitHub AdvisoriesGHSA-j4qf-3w33-8cgc 8.1

SimpleSAMLphp Signature validation bypass

A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. A SimpleSAMLphp Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP.

Record
GHSA-j4qf-3w33-8cgc
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-347
Updated
2026-11-02
OSV 8.1

A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. A SimpleSAMLphp Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP.

Record
CVE-2017-18122
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVDEBIAN-CVE-2017-18122 8.1

A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. A SimpleSAMLphp Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP.

Record
DEBIAN-CVE-2017-18122
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVGHSA-j4qf-3w33-8cgc 8.1

SimpleSAMLphp Signature validation bypass

A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. A SimpleSAMLphp Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP.

Record
GHSA-j4qf-3w33-8cgc
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-347
Updated
2026-11-02
OSVUBUNTU-CVE-2017-18122 8.1

A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. A SimpleSAMLphp Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP.

Record
UBUNTU-CVE-2017-18122
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
simplesamlphp/simplesamlphp
Packagist
before 1.14.17
1.14.17
simplesamlphp
Debian:12
before 1.15.0-1
1.15.0-1
simplesamlphp
Debian:14
before 1.15.0-1, plus listed versions
1.10.0-11.11.0-11.12.0-11.12.0~rc1-11.12.0~rc2-1
Show 34 moreShow less
1.13.0-11.13.1-11.13.1-21.13.2-11.14.0-11.14.1-11.14.10-11.14.11-11.14.15-11.14.2-11.14.2-21.14.3-11.14.4-11.14.5-11.14.6-11.14.7-11.14.8-11.14.9-11.6.0-11.6.1-11.6.2-11.6.3-11.6.3-21.6.3-31.7.0-11.7.0-21.8.0-11.8.1-11.8.2-11.9.0-11.9.0~rc1-11.9.0~rc2-11.9.1-11.9.2-1
1.15.0-1
simplesamlphp
Debian:7
before 1.9.2-1+deb7u2, plus listed versions
1.9.2-11.9.2-1+deb7u1
1.9.2-1+deb7u2
simplesamlphp
Debian:8
before 1.13.1-2+deb8u1, plus listed versions
1.13.1-2
1.13.1-2+deb8u1
simplesamlphp
Debian:9
before 1.14.11-1+deb9u1, plus listed versions
1.14.11-1
1.14.11-1+deb9u1
simplesamlphp/simplesamlphp
Packagist
before 1.14.17, plus listed versions
v1.12.0v1.13.0v1.13.0-rc1v1.13.0-rc2v1.13.1
Show 19 moreShow less
v1.13.2v1.14.0v1.14.0-rc1v1.14.1v1.14.10v1.14.11v1.14.12v1.14.13v1.14.14v1.14.15v1.14.16v1.14.2v1.14.3v1.14.4v1.14.5v1.14.6v1.14.7v1.14.8v1.14.9
1.14.17
simplesamlphp
Ubuntu:Pro:16.04:LTS
All versions, plus listed versions
1.13.2-11.14.0-11.14.0-1ubuntu21.14.0-1ubuntu2+esm1
None known

History

History
WhenChangedSources
2026-11-03aliasesEUVD
2026-11-02createdCVE List, GitHub Advisories, NVD, OSV

References

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